Preparation of derivatives of



Patented May 5, 1953 UNITED STATES PATENT OFFICE PREPARATION OF DERIVATIVES- F lA-DI- AMINOBENZENE- N- SULFONIC ACID Robert Lazare Lantz Paris, and Gilbert Henri Victor Krmcr, Ermont, France, assignors to Compagnic Francaise des Matieres Colorantcs S. A. R. L., Paris, France, a company of France No Drawing; Application March 20, 1951, Serial No. 216,666. In France November 30, 1950 3 Claims. (Cl. 260-500) The present invention relates to water soluble salts of 1, l-diaminobenzene-N-sulphonic acid.

In particular it relates to water soluble salts of those 1,e-diaminobenzene-N-sulphonic acid the amino group in the 1 position of which is substituted with a hydrocarbon radical, having the general formula where R is a hydrocarbon.

It has been found that water soluble salts of the 1,4-diaminobenzene-N-sulphonic acid, the amino group in the 1 position of which is sub-g can be one selected from the group which con sists of caustic alkalis, alkali metal carbonates or alkali metal sulphites. Alkali metal salts of certain primary arylamines the amino group of which is substituted ErampZe.-A mixture containing parts of N(4-nitrophenyl)-amino benzene, 24.5 parts of sodium bisulphite, 29.? parts of anhydrous sowith a-suiphonic group have already been prcpared by reacting a mixture of sodium sulphite and sodium bisulphite with the correspondingaromatic nitro-derivatives.

However, the reaction does not appear to ha y been carried out on the corresponding nit" derivatives which carry an amino group either unsubstituted or substituted by a hydrocarbon residue; several attempts have already been made I to do this, using bisulphite alone, without sul phite, but they have only given very bad results ticular, in the dyestuffs, dyeing and printing industries'.

In the following example, which illustrates the present-invention, without in any way limiting: it, the quantities are given by weight except where indicated to the contrary.

Y Number dium sulphite, 102 parts of water and parts by volume of alcohol are stirred for four hours at C. in a closed apparatus.

The alcohol is distilled off, after addition of 3 parts of sodium carbonate and sufficient water to give a fllterable solution on completion of distillation. The liquid remaining after this distillation is filtered and allowed to cool to 20 C. Sodium N-phenyl-l, 4-diaminobenzene-N-sulphonate crystallises out. After filtering by suction and drying, it has a very clear colour.

We claim:

1. A process for preparing a water soluble salt of N-phenyl-l, 4-diaminobenzene-N-sulphonic acid which comprises heating an alkali metal bisulphite and a product to raise the pH of the mixture with N(4-nitrophenyl) amino benzene in the presence of water said product to raise the pH of the mixture being a member of the group consisting of caustic alkalies, alkali metal carbonates and sulphites.

2. A process for preparing a water soluble salt of N-phenyl-l, 4-diaminobenzene-Nsulphonic acid which comprises heating an alkali metal bisulphite and a product toraise the pH of the mixture with N(4-nitrophenyl) amino benzene in the presence of water, said product to raise the pH of the mixture being a member of the group consisting of caustic alkalies, alkali metal carbonates and sulphites in which a water misciole solvent is also employed.

3. A process of preparation of sodium N-phenyl-lA-diaminobenzene N sulphonate which consists of heating sodium bisulphite and sodium sulphite with NOl-nitrophenyhamino benzene in the presence of water and alcohol.

ROBERT LAZARE LANTZ. GILBERT HENRI VICTOR KREMER.

References Cited in the file of this patent V UNITED STATES PATENTS Name a Date Dickey et a1. May 13, 1941 OTHER REFERENCES Weil et al.: Chem. Abst., vol. 17, pp. 993-994= 1923) or Ben, vol. 55, pages 25332542 (1922). 

1. A PROCESS FOR PREPARING A WATER SOLUBLE SALT OF N-PHENYL-1, 4-DIAMINOBENZENE-N''-SULPHONIC ACID WHICH COMPRISES HEATING AN ALKALI METAL BISULPHITE AND A PRODUCT TO RAISE THE PH OF THE MIXTURE WITH N(4-NITROPHENYL) AMINO BENZENE IN THE PRESENCE OF WATER SAID PRODUCT TO RAISE THE PH OF THE MIXTURE BEING A MEMBER OF THE GROUP CONSISTING OF CAUSTIC ALKALIES, ALKALI METAL CARBONATES AND SULPHITES. 